The present disclosure relates to containers and methods of making the same. More particularly, the present disclosure relates to containers suitable for packaging high purity solvents, such as hexane, and the use of chemical vapor deposition technology, for example plasma enhanced chemical vapor deposition, for providing a solvent, oxygen, or other bather for such containers.
High purity solvents have many industrial applications, for example, in analytical chemistry, environmental analysis and biotechnology. These solvents are typically stored in glass containers (e.g., bottles or other vessels), because the inert property of glass makes it ideal for storing high purity solvents. However, traditional glass solvent containers are prone to breakage or degradation during manufacture, filling operations, shipping and use, which means that glass particulates may enter the solvent, thus degrading the solvent's purity.
While plastic containers are less prone to breakage, their use as primary packaging for high purity solvents may be limited due to their gas (e.g., oxygen) permeability. The permeability of plastics to gases is significantly greater than that of glass and therefore may be unacceptable as primary packaging for high purity solvents. Further, some high purity solvents, such as hexane, for example, tend to degrade and eat through plastic containers.
The problem of permeability and degradation has been addressed in some applications (for example, pharmaceutical packaging), by adding a barrier coating or layer to a plastic package where it contacts fluid contents of the package. One such barrier layer is a very thin coating of SiOx, applied, for example, by plasma enhanced chemical vapor deposition (“PECVD”). The advantage of using a SiOx barrier coating or layer on, e.g., a plastic vessel, is that in several respects, favorable aspects of both glass and plastic are combined into one package.
An SiOx barrier coating or layer contains silicon, oxygen, and optionally other elements. Barrier coatings and processes of applying them to substrates, e.g., pharmaceutical packages, are described, e.g., in U.S. Pat. No. 7,985,188, which is incorporated herein by reference in its entirety.
While a SiOx-coated plastic container is preferable to an uncoated plastic container for storing high purity solvents, standard containers have drawbacks. For example, three dimensional containers that undergo SiOx coating of their interior surfaces may not be uniformly coated, both in terms of coating thickness and coverage. For example, there is potential that the SiOx coating may miss spots along the interior surfaces of a plastic container. Just as a chain is only as strong as its weakest link, a purportedly SiOx-coated plastic container in which even tiny portions of the interior surface are uncoated or have other imperfections, may be subject to degradation at those vulnerable spots by the contents of the container, e.g., a high purity solvent such as hexane. Accordingly, there is a need for a three dimensional container, e.g., for containing high purity solvents, that is better adapted for more uniform and complete SiOx coating, e.g., using PECVD, than standard three dimensional plastic containers.